Neisseria meningitidis is an important cause of meningitis and sepsis. Conventional approaches to develop a vaccine for prevention of capsular group B disease, which account for a third or more of the cases, have been largely unsuccessful. Current group B polysaccharide-based vaccines present safety concerns through their potential to elicit auto-reactive antibodies. Vaccines using non-capsular antigens have been limited by antigenic diversity and/or poor immunogenicity. Trinity Biosystems (TBS) is developing an antigen delivery platform that appears to have many of the properties desirable for the induction of both potent and durable mucosal and systemic antibody responses. This approach utilizes a non-toxic form of Pseudomonas aeruginosa exotoxin A (ntPE) as a carrier and a potent adjuvant. Insertion of conformational antigenic epitopes into ntPE produces a defined protein that can readily transport across intact mucosal barriers and selectively target professional antigen presentation cells, including dendrictic cells. Children's Hospital Oakland Research Institute (CHORI) is investigating several N. meningitidis antigens that could readily be delivered by ntPE that are potentially useful for the development of a broadly protective meningococcal vaccine. This application, a consortium between TBS and CHORI, describes a number of these potential antigens and methods to characterize and evaluate the potential for ntPE vaccine candidates with the goal of selecting promising leads to move forward into clinical development. Chimera proteins having an inserted peptide antigen will be initially screened using monoclonal antibodies that have been shown to have bactericidal activity against a broad range of group B N. meningitidis strains. Once a desired conformation has been optimized, that ntPE chimera will be characterized to ensure that it retains the ability to transport efficiently across polarized epithelial cell monolayers and to traffic appropriately in target cells (critical for proper antigen presentation) following this transport. Immunogenicity of the chimera proteins will be investigated in mice. Mucosal antibody responses to the bacterial surface and serum antibody responses that are bactericidal will be determined in vitro. Passive protection against meningococcal bacteremia in infant rats will be used to select vaccine candidates for a preliminary safety assessment. The proposed studies will combine immunological and genetic approaches with a novel vaccine platform to select one or two lead candidates for further development.